Method and device for the manufacture of seamless metal bottles

ABSTRACT

A method for the manufacture of seamless metal bottles, particularly so-called aerosol bottles, which are made from a cold-molded, cylindrical blank, open at one end. The open end of the blank is shaped by compression into a bottleneck. The open end of the blank is pressed axially against a rotation surface brought into a conic pendulum motion so that the edges of the opening of the blank are evened and thickened to some extent, and then against another rotation surface, which has also been brought into a pendulum motion so that its axis of symmetry moves like a conic pendulum, at which time the pendulous pole of the conic pendulum is on the central axis of the completed bottle, and the shape of the second rotation surface is approximately that of the completed bottleneck. Only the diameter of its plane section is somewhat greater than the diameter of the respective area of the bottleneck.

[ 1 Sept. 12, 1972 United States Patent Rautavalta [54] METHOD AND DEVICE FOR THE MANUFACTURE OF SEAMLESS METAL BOTTLES [72] Inventor: Juhani Rautavalta, Helsinki, Finland [73] Assignee: Printal 0y, Helsinki, Finland ABSTRACT A method for the manufacture of seamless metal bottles, particularly so-called aerosol bottles, which are made from a cold-molded, cylindrical blank, open at one end. The open end of the blank is shaped by compression into a bottleneck. The open end of the blank is pressed axially against a rotation surface brought into a conic pendulum motion so that the edges of the opening of the blank are evened and thickened to some extent, and then against another rotation surface, which has also been brought into a pendulum motion so that its axis of symmetry moves like a conic pendulum, at which time the pendulous pole of the conic pendulum is on the central axis of the completed bottle, and the shape of the second rotation surface is approximately that of the completed bottleneck. Only the diameter of its plane section is somewhat greater than the diameter of the respective area of the bottleneck.

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METHOD AND DEVICE FOR THE MANUFACTURE OF SEAMLESS METAL BOTTLES- BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to the field of manufacturing seamless metal bottles, e.g., aerosol bottles.

2. Description of the Prior Art One such manufacturing method and device has been introduced in Swedish Pat. No. 224,300. However, when this method is used, the units of machinery will be very large because the shaping of the bottleneck and the mouth require several separate compression phases, and each compression phase requires its own tools and working units, and, thus the machine becomes very large and expensive.

SUMMARY or THE INVENTION According to the inventionthe open end of the blank is pressed axially against a rotation surface which has been brought into a conic pendulum motion so that the edges of the opening are evened and thickened. Thereafter the opening is pressed against another rotation surface, which also has been brought into a pendulum motion so that its axis of symmetry moves like a conic pendulum the pendulous pole of the conic pendulum being on the central axis of the completed bottle. The shape of the last mentioned rotation surface is approximately equal to that of the completed bottleneck, except that the diameter of its plane section is somewhat greater than the diameter of the respective area of the bottleneck.

A device according to the invention includes a frame, a shaft, bearings for attaching the shaft to the frame, a power source connected to the shaft, a tool with a cavity having an opening outside, in which the cavity wall is a rotation surface following the shape of a completed bottleneck at the extreme position of a conic pendulum motion of the tool and completely detached from the surface of the bottleneck on the opposite side thereof, means for connecting the tool to the shaft so that the tool, without rotating, is'brought into the conic pendulum motion, in which the pole of the pendulum is on the rotation axis of the shaft, and means connected to the frame for steering the blank when it is pressed against the rotation surface.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a longitudinal cross section of one application and the can to be compressed in the final phase,

FIG. 2 shows a longitudinal cross section of another application, and

FIG. 3 a longitudinal cross section of a third application, FIG. 4 shows a perspective view of a partly cut machine, in which the compression and the collaring of the can-shaped blank can be carried out in four successive phases.

DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment In the FIGS., 1 refers to the frame of the device, to which the shaft 5, connected to the belt pulley 4, is attached with bearings 2 and 3. Referring to FIG. 1, a bar 6 parallel to the shaft 5 has been adjusted eccentrically inside the shaft 5. At the lower end of the bar 6 there is a flange 7, to which a steering arm 8 has been eccentrically attached with bearings. The lower end 9 of the steering arm 8 is hemispherical and adjusted to move in a similarly hemispherical seating 10, which, again, is attached to the frame 1.

.The actual tool 12 has been attached on the plane surface of the lower end 9 of the steering arm 8, for example, by a bolt 11. The tool 12 has a cavity 13 open at its lower end, and its wall is a rotation surface, the diameter of which is greater in a plane section than that of the compressed bottleneck in the same plane section; the ratio of these diameters changes preferably linearly. In the middle of the bottom of the cavity 13 there is a bar 14, which narrows somewhat conically downward and to the rootof which has been made a ringlike, downward widening groove 15 with a rounded bottom; theouter border ofthe groove 15 ends at the rotation surface of the cavity 13.

A steering ring 16 has been fitted to the lower part of the frame 1. Its inner diameter is the same-as the outer diameter of the bottle blank 17, and it works as a steering apparatus of the blank when it is pressed against the rotation surface of the cavity 13.

Operation 1 The belt pulley 4 is made to rotate through belt driving by some driving apparatus not shown, at which time the shaft 5 begins a rotational motion, and the bar 6 and the upper end of the steering arm 8 attached eccentrically with bearings to the flange at the lower end of the'bar 6 move eccentrically in relation to the shaft 5 along the circumference of a circle, the radius of which can be adjusted by turning the bar 6 inside the shaft 5. The axis of the steering arm then forms the desired angle with the shaft 5, depending on the adjustment of thebearings of the lower end 9 of the steering arm 8. In this manner the steering arm 8 and the tool 12 attached to its lower end are brought into a conic pendulum'motion, in which the tool 12 does not rotate around its own axis at all.

When the straight cylindrical blank, open at one end, is pressed through the steering ring 16 against the rotation surface wall of the cavity 13 of the tool 12, the open end of the blank is gradually molded into the shape shown in the figure, at which time the collaring of the mouth of the bottle is also completed. The shape of the completed bottleneck naturally depends on the shape of the cavity of the tool, and because the tool and the steering ring can be easily changed and the conic angle of the conic pendulum swing can be easily and quickly adjusted, it is profitable to manufacture even short series of bottles with the machine.

Second Embodiment FIG. 2 shows another example of a device applicable to the carrying out of the method according to the invention, and the same numbers are used as in FIG. 1 to refer to the respective parts of the device. In this device, a bearing box 18 has been fitted to the flange 7 at the lower endof the shaft 5, which is made to rotate with the help'of a belt pulley 4, and the upper end of the steering arm 8 has been attached to the bearing box eccentrically with bearings so that by turning the bearing box the eccentricity of the arm 8 can be changed in relation to the shaft 5 as well as the conic angle of the conic swing to the tool 12 forming the lower end of the steering arm. The tool 12 has been cardanically pended with the cardan ring 19 of the opening 1. The drawing shows the journals 20 attached with bearings to the cardan ring of the tool 12, but those journals which are attached to the frame at an angle of 90 in relation to the first mentioned journals and which are attached with bearings to the cardan ring, are not shown in the drawmg.

Operation The' shaping of the bottleneck takes place in this device in the same manner as in the device according to FIG. 1, however, with the difference that the grooving causing the-collaring has been left out in the tool of the device according to FIG. 2. Thus, the mouth of the bottle remains straight in this case.

Third embodiment I FIG.;3 shows a third example of a device applicable to thec'arrying out of the method according to the invention, and the same numbersare. used as in FIGS. 1 and 2 to refer to the respective parts. In this device'the belt pulley 4 has been molded directly at the upper end of the hollow shaft 5, which has been attached to the frame 1 with bearings 2 and 3. The inner and outer diameters of the hollow lower end 21 of the shaft 5. are greater than those of its upper end. The lower edge 22 of thelower end 21 of the shaft has been cut obliquely so that the outer ledges 23 of the tool 12 to be pushed into the cavity of the lower end 21 of the shaft 5 set the tool 12 in an oblique position when they come into contact with the lower edge 22 through bearings 24. The lower part of the tool 12 has been provided with abottle surface 25, which leans against the respective spherical surface of the ringlike steering apparatus 26 attached to the frame 1.

Operation Wh'en'the shaft 5 is brought into rotational motion, the tool '12 begins a conic pendulum motion without rotating around its own axis at all, and the shaping of the bottleneck takes place as has been described in connection .with FIG. 2. I

The'molding'of the opening of the can, the purpose of which is to compress the diameter of the opening and to collar the edge of the compressed part, takes place in four phases.

First phase. Preliminary working of the edge. The edge of the opening of the can, the thickness of the wall of which usually varies between 0.40 and 0.50 mm, depending on the diameter, istoo weak to endure the following compression phase without getting dented. Even a small unevenness of the edge or an accumulation of laquer is a sufficient discontinuity from which the can begins to dent. By treating the edge of the can so that it becomes quite even and simultaneously thickens over a small distance, it is possible to cornpress a thin-walled can in one phase without denting the Wall and without being compelled to use thickerwalled cans, which would be uneconomical in regard to the consumption of aluminum.

The preliminary working of the edge is done with the tool in a conic pendulum motion. The can to be worked is pressed against the swinging tool. At this time the edge of the can is shaped at the point touching the tool. Even though the force pushing the can is relatively insignificant, the edge of the can is shaped, for the actual contact surface is small and the surface pressure relatively great. Not even a thin-walled can will be harmed because the force pushing the can-shaped blank can be keptsmall.

Second phase. Compression of the can as has beenexplained above.

Third phase. Cutting of the edge. Especially when large cans are compressed, unevenness may be formed along the edge, which makes an even collaring difficult.

Therefore it is advantageous to cut 1-2 mm off from the compressed can. This takes place with a rotating blade, which chips the edgeof the can. I

Fourth phase. Collaring. The edge of the compressed and out can is collared by turning it outward. The collaring can take place in three different manners, name ly, by upsetting, with a tool in a conic pendulum motion, or by rolling. It is best to carry out the rolling with a tool formed by a rotating bar joining the middle axis of the bottle, with one or more rollers, rotating at an angle of in relation to the said axis and attached to the bar with bearings. There is a groove in the roller, and the mouth of the bottle is pressed against this groove to cause collaring.

In FIG. 4, 27 refers to the first phase, in which the preliminary working of the edge takes place; 28 refers to the second phase, in which the can is compressed in one phase; 29 refers to the third phase, in which the edge is out even; 30 refers to the collaring phase. 31 is a cam that imparts motion to the cylindrical blank in the direction of its longitudinal axis; 32 is a clamp that holds the can during the working phase and moves it from one phase to another; 33 is a conveyor that moves the clamp .32 intermittently from one working phase to another; 34 is the can to befed to the open clamp; 35 is the belt that conveys the can to the machine; 36 is the upper frame that can be moved according to the length of the can.

The unit of apparatus, or compression unit, applicable to the carrying out of the method according to the invention can be easily connected to the production line of bottles, in which case the following advantages, among other, are obtained:

l. The structure of the compression machine according to the invention is light and simple. The machine consists of, for instance, a chain conveyor and'the actual compression unit.

Because the shaping of the can takes place in one or only a few phases, no complicated dividing wheel and feeding apparatus are needed.

2. The compression machine can be easily connected to an automatic can printing line. In that case, theconveyor of the machine receives its motion from the chain of the line. The impulses needed by the compression unit can be taken from the conveyor.

3. By combining several compression machines to a molding line it is possible to compress directly the entire production of a molding line without human labor.

.4. The adjustment of the compression machine to a compression work. This makes the degreasing of the cans before packing unnecessary and decreases packing expenses.

The absence of a center pin widens the tolerance margin of the wall thickness of the can blank.

6. The method makes it possible to carry out compression of difficult shapes. v

7. Because the force required for the axial feed of the can is quite small it is possible to compress very thinwalled cans. This characteristic makes it possible to save raw material in certain cases.

The invention is not limited to the devices described and illustrated above, but they can be altered in many different ways within the following patent claims.

What is claimed is:

1. A device for manufacturing seamless metal bottles, especially aerosol bottles, from a cold molded, cylindrical blank open at one end, comprising:

a frame;

a shaft; I

bearings for attaching the shaft to the frame;

a power source connected to the shaft for rotating it;

a tool having a cavity with an opening outside and the wall of the cavity being a rotation surface adapted to follow the shape of a completed bottleneck at the extreme position of a conic pendulum motion of the tool and being completely detached from the surface of the bottleneck on the opposite side thereof;

means for connecting the tool to the shaft so that the tool, without rotating, is brought into the conic pendulum motion, in which the pole of the pendulum is on the rotation axis of the shaft; and

means connected to the frame for steering the blank during its pressing against the rotation surface.

2. A device as recited in claim 1, wherein the means for connecting the tool to the shaft comprises:

a steering arm having a hemispherical lower end;

a hemispherical seating attached to the frame; and

bearings for attaching the hemispherical lower end of the steering arm to the hemispherical seating the tool being attached to the lower surface of the lower end of the steering arm.

3. A device as recited in claim 1, wherein the means for connecting the tool to the shaft comprises a steering arm the lower end of which forms the tool and attached eccentrically to the lower end of the shaft, and wherein the tool has been attached to the frame with bearings through a cardan ring.

4. A device for manufacturing seamless metal bottles as aerosol bottles from a cold molded, cylindrical blank open at one end, comprising:

a frame;

an open hollow shaft having an oblique annular edge surrounding its opening;

bearings for attaching the frame to the shaft;

a power source connected to the shaft for rotating it;

a tool having an external ring ledge and a cavity with an opening outside the wall of the cavity being a rotation surface adapted to follow the shape of a completed bottleneck at the extreme position of a conic pendulum motion of the tool and being completely detached from the surface of the' bottleneck on the op osite side thereof, bearings between t e oblique annular edge of the shaft and the external ring ledge of the tool so that the tool rests against the oblique edge and is brought into the conic pendulum motion, in which the pole of the pendulum is on the rotation axis of the shaft;

a ring at the lower end of the tool and having a spherical surface;

a steering means attached to the frame and having a spherical surface corresponding to the spherical surface of the tool, which leans against the steering means; and

means connected to the frame for steering the blank during its pressing against the rotation surface. 

1. A device for manufacturing seamless metal bottles, especially aerosol bottles, from a cold molded, cylindrical blank open at one end, comprising: a frame; a shaft; bearings for attaching the shaft to the frame; a power source connected to the shaft for rotating it; a tool having a cavity with an opening outside and the wall of the cavity being a rotation surface adapted to follow the shape of a completed bottleneck at the extreme position of a conic pendulum motion of the tool and being completely detached from the surface of the bottleneck on the opposite side thereof; means for connecting the tool to the shaft so that the tool, without rotating, is brought into the conic pendulum motion, in which the pole of the pendulum is on the rotation axis of the shaft; and means connected to the frame for steering the blank during its pressing against tHe rotation surface.
 2. A device as recited in claim 1, wherein the means for connecting the tool to the shaft comprises: a steering arm having a hemispherical lower end; a hemispherical seating attached to the frame; and bearings for attaching the hemispherical lower end of the steering arm to the hemispherical seating the tool being attached to the lower surface of the lower end of the steering arm.
 3. A device as recited in claim 1, wherein the means for connecting the tool to the shaft comprises a steering arm the lower end of which forms the tool and attached eccentrically to the lower end of the shaft, and wherein the tool has been attached to the frame with bearings through a cardan ring.
 4. A device for manufacturing seamless metal bottles as aerosol bottles from a cold molded, cylindrical blank open at one end, comprising: a frame; an open hollow shaft having an oblique annular edge surrounding its opening; bearings for attaching the frame to the shaft; a power source connected to the shaft for rotating it; a tool having an external ring ledge and a cavity with an opening outside the wall of the cavity being a rotation surface adapted to follow the shape of a completed bottleneck at the extreme position of a conic pendulum motion of the tool and being completely detached from the surface of the bottleneck on the opposite side thereof, bearings between the oblique annular edge of the shaft and the external ring ledge of the tool so that the tool rests against the oblique edge and is brought into the conic pendulum motion, in which the pole of the pendulum is on the rotation axis of the shaft; a ring at the lower end of the tool and having a spherical surface; a steering means attached to the frame and having a spherical surface corresponding to the spherical surface of the tool, which leans against the steering means; and means connected to the frame for steering the blank during its pressing against the rotation surface. 